Solid Particle Dispersion Technology
Langen et at., in U.K. Pat. No. 1,570,362 disclose the use of solid particle milling methods such as sand milling, bead milling, dyno milling, and related media, ball, and roller milling methods for the production of solid particle dispersions of photographic additives such as couplers, UV-absorbers, UV stabilizers, white toners, stabilizers, and sensitizing dyes.
Henzel and Zengerle, in U.S. Pat. No. 4,927,744, disclose photographic elements comprising solid particle dispersions of oxidized developer scavengers. Said dispersions are prepared by precipitation and by milling techniques such as ball-milling.
Boyer and Caridi, in U.S. Pat. No. 3,676,147, disclose a method of ball-milling sensitizing dyes in organic liquids as a means of spectrally sensitizing silver halide emulsions. Langen et al., in Canadian Patent No. 1,105,761, disclose the use of solid particle milling methods and processes for the introduction of sensitizing dyes and stabilizers in aqueous silver salt emulsions.
Swank and Waack, in U.S. Pat. No. 4,006,025, disclose a process for dispersing sensitizing dyes, wherein said process comprises the steps of mixing the dye particles with water to form a slurry and then milling said slurry at an elevated temperature in the presence of a surfactant to form finely divided particles. Onishi et al., in U.S. Pat. No. 4,474,872, disclose a mechanical grinding method for dispersing certain sensitizing dyes in water without the aid of a dispersing agent or wetting agent. This method relies on pH control in the range of 6-9 and temperature control in the range of 60.degree.-80.degree. C.
Factor and Diehl, in U.S. Pat. No. 4,948,718, disclose solid particle dispersions of dyes for use as filter dyes in photographic elements. They disclose that such dyes can be dispersed as solid particle dispersions by precipitating or reprecipitating (solvent or pH shifting), by ball-milling, by sand-milling, or by colloid-milling in the presence of a dispersing agent.
Iwagaki et al., in unexamined Japanese Kokai No. Sho 62[1987]-136645, disclose solid particle dispersions of heat solvent, wherein said heat solvent has a melting point of 130.degree. C. or greater. These heat solvent dispersions are incorporated in a thermally developed photosensitive material incorporating silver halide, a reducing agent, and a binder on a support, wherein said material obtains improved storage stability. Komamura and Nimura, in unexamined Japanese Kokai No. Hei 4[1992]-73751, disclose a ball-milled dispersion of the following compound (TS-i): ##STR1##
A novel method of imaging, whereby conventional aqueous development processes are utilized in combination with substantially dry thermally activated diffusion transfer of image dyes to a polymeric receiver has been described by Willis and Texter in commonly assigned U.S. application Ser. No. 07/804,877, filed Dec. 6, 1991, Heat Image Separation Systems, by Bailey et al. in commonly assigned U.S. application Ser. No. 07/804,868, filed Dec. 6, 1991, Thermal Solvents for Dye Diffusion in Image Separation Systems, by Texter et al. in commonly assigned U.S. application Ser. No. 07/927,691, filed Aug. 10, 1992, Polymeric Couplers for Heat Image Separation Systems, and by Texter et al. in commonly assigned U.S. application Ser. No. 07/993,580, filed Dec. 21, 1992, Dye-Releasing Couplers for Heat Image Separation Systems.
The morphology of a photographic element for such systems generally consists of a (1) dimensionally stable support of transparent or reflection material, (2) a receiver layer to which the diffusible dyes migrate under thermal activation, (3) optionally a stripping layer, (4) one or more diffusible-dye forming layers in which the light image is captured and amplified during conventional aqueous color development, and (5) a protective overcoat. Latent image in the diffusible-dye forming layers is captured using well known silver halide technology and these images are amplified in conventional aqueous color development. After aqueous development the element is subjected to a stop/wash bath, dried, and then heated to drive the diffusible-dye image to the receiver. Thereafter, the support and receiver layer are separated from the diffusible-dye forming layers by a stripping method, such as that disclosed by Texter et al. in U.S. Pat. No. 5,164,280, Mechanicochemical Layer Stripping in Image Separation Systems. The separated diffusible-dye forming layers may subsequently be used as a source of recoverable silver and other fine chemicals.
Komamura and Nimura, in unexamined Japanese Kokai No. Hei 4[1992]-73751, disclose a method for forming images, where said method uses a photographic material having a support and a photosensitive silver halide layer containing dye-producing material, binder, and a thermal solvent, image exposure, liquid development, lamination of said developed material to a receiver, and heating of said laminate.